pussuw commented on a change in pull request #5782: URL: https://github.com/apache/incubator-nuttx/pull/5782#discussion_r840270240
########## File path: arch/risc-v/src/common/riscv_percpu.c ########## @@ -0,0 +1,117 @@ +/**************************************************************************** + * arch/risc-v/src/common/riscv_percpu.c + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. The + * ASF licenses this file to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance with the + * License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the + * License for the specific language governing permissions and limitations + * under the License. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> +#include <nuttx/irq.h> + +#include <arch/barriers.h> + +#include <assert.h> +#include <stdint.h> + +#include "riscv_internal.h" +#include "riscv_percpu.h" + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +#define HART_CNT (CONFIG_ARCH_CPU_COUNT) + +/**************************************************************************** + * Private Data + ****************************************************************************/ + +static struct riscv_percpu_s g_scratch[HART_CNT]; + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: riscv_percpu_init + * + * Description: + * Initialize the per CPU structures, should only be done on the boot + * hart. + * + ****************************************************************************/ + +void riscv_percpu_init(void) +{ + int i; + + for (i = 0; i < HART_CNT; i++) + { + g_scratch[i].hartid = i; + } +} + +/**************************************************************************** + * Name: riscv_percpu_get_addr + * + * Description: + * Get add a hart to the per CPU area + * + * Input Parameters: + * hartid - Hart number + * + ****************************************************************************/ + +void riscv_percpu_add_hart(uintptr_t hartid) +{ + /* Hart IDs go from 0...4 */ + + DEBUGASSERT(hartid < HART_CNT); + + /* Set the scratch register value to point to the scratch area */ + + WRITE_CSR(sscratch, &g_scratch[hartid]); + + /* Make sure it sticks */ + + __DMB(); +} + +/**************************************************************************** + * Name: riscv_percpu_get_hartid + * + * Description: + * Get harts own hartid by reading it from the per CPU area. This is safe + * to use from lower privilege modes (than M-mode). + * + * Returned Value: + * Hart id + * + ****************************************************************************/ + +uintptr_t riscv_percpu_get_hartid(void) +{ + uintptr_t scratch = READ_CSR(sscratch); Review comment: The intent was to use sscratch only for the percpu structure at least for now. This can be extended later. Asking for hartid in m-mode is simple, just `READ_CSR(mhartid); ` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: commits-unsubscr...@nuttx.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
